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W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS Sept. 28 1926 Filed May 3, 1926 7 Sheets-Sheet l INVENTOR William A51! le.

ATTORNEYS Vice Sept. 28 1926. 1,601,591

w. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS m Filed May 5, 1926 '7 Sheets-Sheet 2 3 INVENTOR l I/z'llz'm Astle.

ATTORNEYS Sept. 28 19.26.

W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS v 7 Sheets-Sheet 5 Filed May 5, 1926 6355 sux V. UMNUN INVENTOR I William A6116 ATTORNEYS Sept. 28, 1926.

W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS "r Sheets-Sheet 4 INVENTOR 14/17/1727 As 16.

Filed May 5, 1926 ATTORNE Y Sept. 28 1926.

W; ASTLE CONTROL VALVE F'OR AIR BRAKE APPARATUS Filed May 3, L926 '7 Sheets-Sheet 5 ATTORNEYS 6 \NN Qm Sept. 28 1926 W. ASTLE CONTROL VALVE FOR AIR BRAKE APPARATUS Filed May 1926 *7 Sheets-Sheet 6 \ZIIZZZZIIT.

INVENTOR William A611 ATTORNEY5 INVENTOR William A5116 ATTORNEYS Patented Sept. 28, 1926.

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WILLIAM ASTLE', OF; BRGOK-LYN, NEW YDRK, ASSEGNOR TOAUTOMATIC STRAIGHT AIR BRAKE- COMPANY, 9F WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE;

CONTROL VALVE FOR AIR-BRAKE APPARATUS.

I Application filed May 3, 1926. Serial No. 106,351.

This invention. relates to a control valve for an air brake apparatus in which a service reservoir supplies air' for service applications of the brakes and an emergency reservoir supplies air for emergency applications of the brakes, an auxiliary'reservoir being provided to supply air pressure for moving the operative parts of the control valve in service and inemergency applications of the brakes, said auxiliary reservoir also being connected to the brake cylinder in emergency applications ofthe brakes. The con trol valve'is provided with a brake cylinder pressure graduating pilot valve; with a service application valve by means of which the brake cylinder pressure may bebuilt up at a predetermined ratio to the reduction of brake pipe pressure; and with an auxiliary reservoir pressure equalizing valve.

The main objects of the invention are:

let: To provide a control valve which, in service application position, will connect a service reservoir to the brake cylinder;

2nd: To provide a control valve which, in emergency position, will connect an emergency reservoir and an auxiliary reservoir to the brake cylindenthe service reservoir being sealed;

3rd: To provide a: control valve wherein the main slide valve in emergency position will permit auxiliary reservoir air to open a brake pipe vent valve, the main slide valve in emergency position also operating to open an emergency valve to permit emergency reservoir air to flow to the main slide valve chamber and thence to the brake cylinder for an emergency application of the brakes;

4th: To provide a control valve having an auxiliary reservoir pressure equalizing valve which when the brake pipe pressure and the auxiliary reservoir pressure equalizes the auxiliary reservoir, the main slide valve chamber, the brake cylinder chamber of the equalizing valve, the control chamber otthe application valve and, the brake cylinder pressure chamber of the graduated release valve will all be-connected together and the pressures therein equalized and maintained therein cut oil from the brake pipe, whereby the brake pipe pressure may be reduced be low the said point of equalization without reducing the brake cylinder pressure. The brake cylinder pressure will be maintained at the degree of equalization;

5th: To provide a control valve operating upon an increaseot brake pipe pressure to connect the auxiliary reservoir and the main valve chamber to the brake pipe whereby pressure in the auxiliary reservoir above the brake pipe pressure will be discharged back into the brake pipe. This feature of the invention isadapted to operate when the brake pipe pressure has been reduced below the auxiliary reservoir pressure at which time the auxiliary reservoir has been sealed and cut off from the brake pipe;

6th: To provide a control valve with graduatedrelease pilot valve by means of which the brake cylinder pressure may be graduated off in response to increases in brake pipe pressure 7th: To provide a control valve for air brake apparatus with an application valve havinga control chamber and a brake cylinder chamber, the pressure in the control chamber openingth'e application valve to permit air to flow to the brake cylinder pres sure chamber and to the brake cylinder, the pressure in said brake cylinder pressure chamber controlling; the closure of the application valve;

8th: To provide a control valve with a quick-release valve'co operating with a manually adjustable release-governing valve whereby a portion of the emergency reservoir air will be discharged into the brake pipe when the control valve is in release position 9th: To provide a control valve with meansitor retarding the recharging of reservoirs and restricting the release of brake cylinder pressure when there is an excessive brake pipe pressure.

There are other important objects and advantages of the invention, all of which will appear hereinafter-.-

In the drawings, Figure 1 is a diagrammatic sectional view showing the parts of the control valve in release and charging positions;

Fig. 2 a partial diagrammatic sectional view showing the parts of the control. valve in service application position;

Fig. 3 a view similar to Fig. 1, showing the parts in release position after a service application Fig. 4 a diagrammatic view similar to Fig. 2, showing the parts of the control valve in emergency position;

Fig. 4 a detail sectional view of the valve which controls the opening of the brake pipe vent valve in emergency operations;

Fig. 5 asectional diagrammatic view of a portion of the control valve, showing the parts in retarded recharging and restricted release position;

Fig. 6 a diagrammatic sectional view of a portion of the control valve showing the release-governing valve in graduated-release position;

Fig. 7 a-diagrammatic sectional view of a portion of the control valve showing the main and supplemental slide valves in service lap position; and

Fig. 8 a diagrammatic view of the control valve, its associated reservoirs and the brake pipe and brake cylinder.

In order to simplify the description of the control valve and its operations, the various parts and the ports and passages will not be specifically described except in connection with the description of the vari us operations of the valve.

In the diagrammatic view Fig. 8, A designates the control valve; B the brake cylinder;- C the brake pipe; D the service reservoir; E the emergency reservoir; and F the auxiliary reservoir.

In the control valve is formed a main valve chamber 1. In this chamber is arranged a main actuating service piston 2. The piston 2 separates the main valve chamber 1 from an auxiliary reservoir chamber 6 to which the auxiliary reservoir F is directly connected. The brake pipe is connected to the main valve chamber so that brake pipe pressure ison the inner side of the piston 2 and the auxiliary reservoir pressure is on the outer side of said piston. The piston 2 is formed with an outwardly extending tubular extension 3 in which is arranged aspring 5. Arranged in the tubular extension and directly engaging the spring 5 is a normal charging stop 4. The outer end of this spring-pressed stop is adapted to engage a rigid stop 7 to hold the piston 2 and the connected valves in normal charging position. The stop 4: will yield under an excessive brake pipe pressure in chamber 1 and permit the piston and the connected valves to move outwardly to retardedcharging position. The stop 4 is arranged to normally hold the piston 2 slightly in wardly from a stop wall 7 so that an excessive brake pipe pressure will force the piston 2 outwardly a ainstthe tension of the spring 5 until'said piston abuts against extending valve-engaging portion8, said inwardly extending portion also serving as a guide'for the piston and for the valve connected thereto. On the main valve seat 9 is arranged a main slide valve 10, and on top of said valve 10 is arranged a supplemental slide valve 11, this latter valve being connected to the piston 2 by the inwardly extending part 8. The valve 11 moves with the piston 2 and slides on topof the main valve 10. The inward movement of the piston 2 to service application position is positively limited by the said piston contacting with the abutment 9, said abutment being the end of the valve seat.

In the opposite end of the main valve chamber 1 from the piston 2 is arranged a small emergency piston 12, said piston also serving as a service lap stop to arrest the supplemental slide valve in service lap position. The piston 12 is formed with an inwardly extending, central, tubular part 13 having an inner stop wall 1 1 which is adapted to serve as a service stop or abutment for the supplemental valve 11. The inner guide portion 8 of the extension'8 is adapted to engage the stop wall 14. Secured to the outer face of the piston 12 is an out wardly extending tubular extension 15 which is formed with an inwardly extending flange 15 on its outer end. WVithin the tubular part 13 and the tubular extension 15 is arranged a service lap stop spring 16, said spring holding a washer 17 against the flange 15 Formed on the valve casing in axial alinement with the spring 16 is an abutment 18 which extends into the tubular part 15 and contact-s with the washer 17. The spring 16 serves as a means to hold the emergency piston 12 in its inner position, a stop 19 being arranged to hold the emergency piston in its correct normal position and also serving to hold the main slide valve in its noris normally in said chamber 29.

malservice and release position. The emer gency piston 12 serves to separate the supplemental brake pipe chamber 1 from the main slide valve chamber 1, and said piston carries on its outer face 'aigasket which, in the emergency position of the piston 12, engages an annular rib and seals the supplemental brake pipe chamber. The eXten sion 13 of the piston 12 is connected by a pin 2 to the main slide valve. The pin 21 is rigidly connected to the main slide valve and extends up into a slot in the extension 13 so that the piston 12 may have a slight outward movement,that is to say toward the right hand as viewed in the drawings without movingthe main slide valve. The slot forms a lost-motion connection between the piston 12 and the main slide valve. The main slide valve remains in its normal position during all operations of the supplemental valve and only moves to emergency position as will be hereinafter described. The main valve chamber is connected to the supplemental brake pipe chamber 1 by a passage 22 in which is arranged a restriction plug 23. The purpose of this plug is to limit the restriction of brake pipe pressure in chamber 1 to a'service rate. The brake pipe is connected at O to a brake pipe chamber 24 and said chamber is connected to the supplemental brake pipe chamber 1, as will be hereinafter described, so that air will flow from the chamber 24 into the chamber 1 and thence through passage 22 into the main valve chamber. The control valve is provided with a manually operable release-governing valve which consists of a slide valve 26 connected by a stem 27 to an operating rod 28. The stem 27 extends through an operating slot 27". To place the valve 26 in quick-release position the operating rod is pulled out, as shown in Fig. 1; and to place it in graduated-release position the said rod is shoved inwardly as shown in Fig. 6. The valve 26 is arranged in a valve chamber 29 and the outer end of this valve chamber, that is to say the left-hand end as viewed in the drawings, is closed by an eXhaust-rate-regulating piston 30. Connected to this piston is an exhaustrate-regulating valve 31. A spring 32 bears on the outer side of the piston 30 and holds the valve 31 in its normal release position. The release-governing valve chamber 29 is connected directly to the main valve chamber 1 by passage 118, so that brake pipe pressure will be always registered in said chamber 29.. Chamber 29 at the outer side of the piston 30 is normally connected to the main brake pipe chamber through passage 119 and port 120 of the main slide valve, so that brake pipe pressure When there is an excessive brake pipe pressure in the main valve chamber 1 chamber 2t will be vented'to atmosphere and the valve 31 will be moved into retarded-release position by the pressure in chamber 29, all 01 which will be more fully hereinafter described.

Release and charging.

In charging the system brake pipe air flows through the brake pipe connection G into the brake pipe chamber 24 and through passage 25 into the brake pipe chamber of the auxiliary reservoir pressure equalizing valve mechanism H.

The auxiliary reserv ir pressure-equalizing valve mechanism H comprises a pair of parallel diaphragms 3i and 35 which are suitably spaced apart and secured around their marginal edges in a suitable valve cas ing, Between the two diaphragms is formed achamber which is open to atmosphere. An equalizing control chamber 36 is formed be tween the diaphragm 35 and the lower wall of the valve casing. Between the upper diaphragm 3st and the upper wall of the valve casing is formed the brake pipe chamber 33. The diaphragm carries a central upwardly extending stop stem 37 which is adapted to engage the upper wall of the chamber to limit the upward movement of the diaphragms. The lower diaphragm 35 carries a central depending stop 38 which is adapted to engage the lower wall of the valve casing to limit the downward movement or the diaphragm. In the chamber 33 is arranged a lever 39, said lever being pivoted at one end to the valve casing and connected at its other end to a valve rod 4&0. Said lever is pivotally connected to the stop stem 3'? so that the outer free end of said lever will move up and down in response to the movements of the diaphragms. Connected to the valve rod L0 is an equalizing valve 41. the operation oi which will be more -fully hereinafter described.

The brake pipe air flowing into chamber 33 will depress the diaphragm structure and move the equalizing valve -11 to its lower position uncovering a port 4.2 which opens directly into the chamber of the equz'ilising valve, this chamber being in direct and open communication with the brake pipe chamber Port 12 is connected to a passage 43 which connects with a passage lit leading directly into the supplemental brake pipe chamber 1. Brake pipe press; w will, therefore, flow from chamber through port 42, passages 43 and into the chamber 1 and thence through passage 22 into the main slide *alve chamber 1 and the piston 2 will be moved toward the left hand as viewed in the drawings until the normal chargin stop 4 engages the abutment T. This movement of the piston 2 will place the supplemental valve 11 in normal charging position. The emergency piston will be held against its 7 stop 19 and the main slide valve will be held in its normal position. From the main valve chamber 1 brake pipe air will flow through port 45 in the supplemental slide valve, port 46 in the main slide valve, port and passage 47 to chamber 48. From chamber 48 air will flow past check valve 49 into passage 50 and thence direct into the service reservoir D. The check valve 19 will prevent service reservoir air passing back from the service reservoir to the chamber d8.

From the main valve chamber 1 bral-Ie pipe air will pass through port 51 in the supplemental slide valve 11, port 52 in the main slide valve into port and passage 53. Passage leads into chamber 5 1-, a back pressure check valve being arranged in said passage 53 to prevent the flow of air from chan'iber back through the passage 53; Connected to chamber 54 is a small chamber 56, a back pr i are check valve 57 being arranged between said chambers and permitting air to flow from chamoer 54.- into chamber Chamber 56 is connected by passage 58 to the emergency reservoir E. Connected to the chamber 5% is a small chamber 59, a back pressure check valve (30 being arranged between said chan'ibers so that air may pass from chamber e into the chamber 59. Chamber 59 connected by a passage 61 to the auxiliary reservoir cham her 6. The auxiliary reservoir directly connected to said chamber 6 so that said reservoir and said chamber 6 will be charged with air from chamber past check valve (50, chamber 59 and thence through the passage 61.

The main valve'chamber 1 is directly connected to the release governing valve chamber 29 by passage 118 so that said chamber 29 will be charged from the main valve chamber. Chamber 2% is charged from the main valve chamber through port 120 and passage 119. A passage 62 connects the auxiliary reservoir chamber 6 to the actuating chamber 63 of the graduated release valve mechanism G'so that the said cham ber 63 will be charged from the auxiliary reservoir. The emergency reservoir chamber (rfl ot the graduated release valve mechanism is connected by pipe (35 to a small chamber 66 and said chamber is connected by passage 67 to the emergency reservoir E, so that chamber 64: will be charged with emergency reservoir air.

The brake pipe passage 25 is connected by a passage 71 to the brake pipe chamber 72 of an auxiliary emergency valve 7 The valve 73 is connected to the stem 7d of a piston 75. The piston 75 operates in chamher 72 and separates said chamber from the auxiliary emergency valve chamber 7 6. The chamber 76 is connected by a passage 77 to chamber 54 so that the valve chamber-.76 will be charged with brake pipe pressure from the chamber 54. The brake pipe pressure flowing into chamber 72 will force the piston 75 inwardly to the left-hand end of the chamber 72. The pressures on opposite sides of the piston will be equal when the system is fully charged. Passage 77 is connected by passage 78 to a small chamber 79 so that said chamber will be charged with brake pipe pressure.

Passage 44L leads from the supplemental brake pipe chamber l to a chamber 80 above a supplemental emergency vent valve 81, said valve being normally held to its seat by a spring 82 and the brake pipe pressure in chamber 80.

lVith an excessive brake pipe pressure in chamber 1 the piston 2 will be forced to the left, compressing the normal charging spring 5 until the piston 2 engages the ri id stop wall 7 This will cause a movement or the supplemental slide valve toward the left and move the charging port 51. out of ister with the port 52 and thereby interlow of air to the emergency reser rup a r 118 voir and to the auxiliary reservoir through port and pass The port l5 is provided with an extension 4-5 so that it will remain in communication with port 46 when the port 51 is out of register with port 52 as just described. This will permit brake pipe air LO flow to the service reservoir during the period of excessive pressure in the main valve chamber 1. he excess move ment of the supplemental slide valve toward the left just described, will bring a restricted port 68 in the supplemental slide valve into register with a port 69 of the main slide valve, and said port 69 is in register with a port 70 in the main slide valve seat. Port 70 leads into the large passage 62 which is in directcommunication with chamber 6 and the auxiliary reservoir, so that in the retarded charging position of the supplemental. slide valve the auxiliary reservoir and the service reservoir will be charged but the emergency reservoir will be cut ottfrom the main valve chamber and will not be charged during the period of excesssive pressure in the main valve chamber. The restricted port 68 will retard the charging of the auxiliary reservoir.

Star vice application.

the passage 22 into the chamber 1 and from said 'cha-n'iber through passages 4%, as and port 42 into the chamber 33. The restriction plug 23f'will limit'the reduction ofpressur in chamber 1 to a service rate. The restriction plug 23 is to prevent an immediate emergency reduction of pressure in the main valve chamber when there is an emergency reduction of brake pipe pressure. A service reduction of brake pipe pressure in cl'iamber 1 will result in a movement of the piston 2 inwardly or toward the right as viewed in the drawings, because of the auxiliary reservoir pressure .on the upper or left hand face of the piston 2. The piston 2, and the sup-,

plemental slide valve 11 connected thereto, will move inwardly until the guide 8 engages the'abutmenti la' of the piston 12. The abutment 1 l,'the piston 12 and the piston 2, will continue to move against the tension of' the spring 16 until the lost motion between the abutmentla and the pin 21 is taken up, at which time the piston 2 will have engaged the fixed abutment stop 9*. The supplemental slide valve will then be in service application position as shown in Fig. 2} When the supplemental slide valve is in service position port 69 of the main slide valve registers with port 83 of the supplemental slide valve. Port 83 is connected. by a long passage 84 in the supplemental slide valve to a port 85 in the face of said valve. This port 85 is in register with a port 86 in the main slide valve and this latter'port is in register with'a port 87 in the main slide valve seat. Port 87 is connected to a passage 88 which leads into the equalizing chamber 89 of the graduated release valve structure.

The graduated release valve structure comprises an actuating diaphragm a; an equalizing diaphragm b; and an emergency diaphragm 0. These diaphragms are suitably mounted. in a casing and are parallel with each other to form a series of air chambers. The diaphragm Z) is larger in area than the actuating diaphragm, for a purpose which will hereinafter appear. Between the diaphragm a and-the upper wall of the valve easing isformed the actuating chamber-63. The equalizing chamber 89 is between the actuating diaphragm a and the equalizing. diaphragm 5. Between the diaphragins Z) and 0 is formed a retention chamber 90. The function of this chamber will be fully hereinafter described. Be tween the emergency diaphragms c and the lower wall-of the valve casing is formed the emergency reservoir chamber 64'. The central supports of the diaphragms are in close engagement with each other so that the diaphragms move up and down together, or substantially so,'in accordance with the v riations in the controlling pressures in the chambers of the diaphragm structure. The

emer ency diaphragm. 0 carries a downwardly extending release stop 0 and the.

actuating diaphragm a carries an upwardly extending application stop a, said latter stop being arranged at the upper end of a central stem carried by the actuating diaphragm. In the actuating chamber 63 is arranged a lever 91. One end of this lever ispivoted on a post secured to the wall of the actuating chamber and the other end thereof is connected to a valve rod 92. In termediate its ends the lever 91 is pivotally connected to the upwardly extending stop stem. a so that the lever will be swung up and down by'the up-and-down. movement of the actuating-diaphragm. On the lower end of the valve rod 92 is secured a release valve 93 and said valve is held in its normal lap-position by a spring 94:.

The lower end of the passage 88 is con nected by a passage 95 to the pressure control chamber 96 of an application valve mecl'ianisml. This application valve mechanism. comprises apair of parallel diaphragms 97 and 98 spaced a suitable distance apart to form a brake cylinder release chamber 99 between them. The marginal edges these diaphragms are suitably secured in the valve casing. The pressure control chamber 96 is formed between the lower diaphragm 98 and the lower wall of the valve casing. Between the upper diaphragm 97 and the upper wall of the valve casing is formed a brake cylinder pressure chamber 1.00, said chamber. being in direct and open communication with the brake cylinder B through passage 101. The central supports of the diaphragms 97 and 98 abut against each other so that the diaphragms move up and down together. The diaphragm 97 carries an upwardly extend ing central stem 102; and the diaphragm 98carries a depending central stop 103 which is adapted to engagev a fixed stop which limits the downward travel of the diaphragm. Extending horizontally through the release chamber is a lever 104, one end of said lever being pivoted to a rigid post fixed in the wall of the valve casing. The lever 104; passes through a slot in the central stem of the diaphragm structure and is pivotally connected thereto. The outer free end of the lever 104 is connected to a small slide valve 105, said. slide valve serving as a compensating valve. An application valve 106 is mounted in a passage 107 leading from the service reservoir D into the brake cylinder pressure chamber 100. The application valve is in the form of a check valve which normally seats toward the chamber 100.. A sliding stem 108 is adapted to engage the valve 106, its lower end projecting into the chamber and being adapted to be engaged by the stop stem 102 when the diaphragms aremoved upwardly to apgraduated plication position. When the application valve is un seated by the upward movement of the stop stem 102 service reservoir air will flow from the reservoir D through passage'107 past check valve 109 and then past the application valve into the chamber 100 and thence to the brake cylinder. The check valve 109 prevents the passage of air from chamber 100 back to the service reservoir. In the main slide valve is formed a port and passage 86 as an extension of the port 86. The port 86 registers with a port 110 in the main slide valve seat and said port is connected by passage 111 to the equalizing control chamber 36 of the equalizing valve mechanism. I

When the supplemental slide valve 11 is in service application position, as shown in Fig. 2, auxiliary reservoir air will flow through passage 62, ports and 69, ports and passage 83, 84, 85. From port air will flow through port 86 into passage 88 andthence to chamber 96 of the application valve and to the equalizing chamber 89 of the graduated release valve. From port 86 air will also flow through port and passage 86, port and passage 110-111 into the equalizing control chamber 36 of the equalizing valve. Air will continue to flow from the auxiliary reservoir and chamber 6 until the pressure in chamber 6 has been reduced to an equality with the pressure in chamber 1, or substantially so and the spring 16 will then move the supplemental slide valve to service lap position, as shown in Fig. 7, thereby closing communication between ports 85 and 86 and interrupting the flow of air to the three chambers just mentioned. Chambers 89, 96 and 36 are so proportioned that their combined volume has a predetermined ratio to the volume of the auxiliary reservoir. This ratio is preferably such that the pressure built up in these three chambers will be two-and-one-half times the amount of reduction oi pressure in chamber 1, that is to say, for a ten pound reduction in chamber 1 there will be a twenty-five pound pressure build up in the said three chambers before the supplemental slide valve. is moved to lap position. It is manifest, however, that this ratio of pressure build up may be varied as desired, by varying the volume of the auxiliary reservoir and of the three chambers. The actuating chamber 63 of the pilot valve is connected through passage .62 to the auxiliary reservoir so that the pressure in the actuating chamber will be reduced with the pressure in the auxiliary reservoir and that the diaphragm structure of the graduated release valve will tend to move upwardly. However, air is at the same time flowing into chamber 89, and because of the larger area of the diaphragm Z) the pressure in said chamber will tend to maintain the diaphragm structure substantially in a'balanced condition. tial movement of the diaphragm structure the valve 93 would make an upward idle movement. When the supplemental slide valve has been moved to lap position the downward force exerted by the pressures in chambers 63 and 89 will balance the up passage 101. This flow of air to the brake.

cylinder is entirely independent of the sup pie'mental valve. f

The brake pipe chamber 24 is connected by a passage 112 tothe chamber 113 of the compensating valve 105. Passage 112 is connected by passage 114 to a port'115 in the seat of the compensating valve. A port and passage 116 leads from the compensating valve seat into the chamber 100. The compensating valve is formed with a cavity 117 When the diaphragm structure is moved upwardly to open the application valve the compensating valve is moved upwardly and the'cavity 117 connects port 115 to port and passage 116 so that brake pipe air will flow from chamber 24 through passages 112 and 114 and thence through passage 116 into the brake cylinder chamber 100.

Air will continue to flow from the service reservoir and the brake pipeinto the brake cylinder until thepressure in the chamber 100 is equal to, or slightly exceeds, the pressure in thecontrol chamber 96. The slightly superior pressure in chamber 100 will depress the diaphragms 97 and 98 and permit the application valve 106 to close and move the compensating valve to lap position, thereby interrupting the flow of air to the brake cylinder. In the passage 116 is arranged a checkvalve 121 to prevent high pressurebrake cylinder pressure from flowing back into the brake pipe. Should there be a leak from the brake cylinder and a resulting reduction in pressure in chamber 100, the pressure in the control chamber 96 would move the diaphragms upwardly and place the compensating valve, in application position and also open the application valve. The brake cylinder pressure would be again built up, from the service reservoir and the brake pipe, slightly in excess of the pressure Should there be any slight iniin chamber 96, whereupon the application valve would close and the compensatingcri superior pressure in chamber in chamber 76 to force the piston outwardly, the service stop 75 arresting the piston in service position, as shown in Fig.

2, and the auxiliary emergency valve 7 3 will be moved into service position. The chamber 79 will be connected by a passage 12 cavity 123 of the auxiliary emergency valve and passage 124, to the brake pipe passage "The chamber 79 is directly connected to the valve chamber 76 through the passage '78 so that in the service position of the valve 7 3 there will be an equalization of pressures on opposite sides of the piston 75 and this will prevent the auxiliary emergency valve going to emergency position. In the pas sage 124 is arranged a check valve 125 to prevent air passing from the brake pipe back lo the chamber 79.

It it be desired to increase the brake cylinder pressure a further reduction of brake pipe pressure must be made whereupon the operation just described will be repeated so that the brake cylinder pressure may be increased in steps, if desired, upto the point of equalization of brake pipe pressure with auxiliary reservoir pressure.

When the brake pipe pressure and the auxiliary reservoir pressure have been equalized either by repeated service reductions of brake pipe pressure or by a full service reduction thereof, there will be equal pressures in chambers 36and 33 of the auxiliary reservoir equalizing valve. When this occurs the diaphragms will be balanced and the equalizing valve 41 will be moved upwardly by the spring 126. Spring 126 is normally depressed and under tension because 01" the When the pressure in chambers 36 and SS'h-ave equalized spring 126 will move the equalizing valve upwardly and connect port 42 with port and passage 127 leading to the chamber 36. This will connect chamber 36 to the supplemental brake pipe chamber 7U and to the main brake pipe chamber 1. As hereinbefore pointed out the auxiliary reservoir, in the service position of the supplemental valve, is connected to the chamber and to chambers 96 and 89. It is clear, therefore, that the pressures in the main valve chamber 1; the supplemental brake pipe chamber 1;

the chambers 36, 96 and 89; and the auxilthe ia-ry reservoirwvill be equalized. At

brake valve. pressure will flow into chambers 1 and 1 iromthe brake pipe chamber 24 precisely same time all of these chambers are cut 011 from the brake pipe due to the fact that the port 42 is connected by the equalizing valve to the port and passage 127. It is clear, therefore, that it the brake pipe pre. me be now further reducer such red cti .1 will have no ei'l'ect upon the pressures in all of the chambers which are connected together and in which the pressures equalize just described and the brake cylinder pressure will be unaffected by such further reduction of brake pipe pressure. Brake cylinder leakage will be compensated for from the service reservoir and the check valve 121 will )revent brake cylinder pressure passing baclr to the brake pipe. The trapped pressure in chamber 96 will move the diaphragm structure upwardly to open the application valve if the brake cylinder pressure leaks down.

hen the supplemental slide valve 11 is in service application position the quick release chamber 180 will be vented to atnosphere as hereinafter described.

When the compensating valve is in application position, this also being compensating position, port 244 in the seat of the compensating valve is uncovered. Port 244 is connected to a passage 245 which is connected to port 47 in the seat of the main slide valve. As hereinbefore pointed out passage 4'? leads to the chamber 48 and said chamber is in communication with the service reservoir. It is clear, therefore, that when the compensating valve 105 is in application position brake pipe air may flow from the compensating valve chamber 113 into the service reservoir. The check valve 49 will prevent service reservoir air flowing to the compensating valve chamber should the pressurein said reservoir be superior to the brake pipe pressure in said chamber.

Release after seroiceQm'07c release.

To effect a release of the brakes after a service application the brake pipe pressure must be increased in the usual manner through the manipulation of the engineers The increased brake pipe as described in the charging operation. The increase of pressure in chamber 1 will force the piston 2 and the supplen'iental slide valve to normal release and charging posi tion, as shown in Fig. 3. In the release position of the supplemental slide valve port- 86 of the main slide valve is connected to port 128- 01 the supplemental slide valve.

Port 123 is connected by a passage 129 to 'port 130 and this latter port registers with port 131 of the main slide valve. Port 131 is in communication with port and passage 132 which leads to a port 133 in the seat of the release governing valve26. In the release governing valve is formed a cavity 134,

trol chamber 96 will result in a downward movement of the diaphragms because of the superior pressure in the brake cylinder chamber 100. The lever 10 1 and the compensating valve will be moved clownwardly, but the movement 01'' the compensating valve will be an idle one. A brake cylinder release valve 136 is arranged in a chamber 137, said valve being in the form of a ball check valve held to its seat by a spring 138. The chamber 137 is connected by passage 139 to the release chamber 99, and extending through said passage is a pin 1 1-0, the lower end of said pin engaging the valve 136 and the upper end thereof engaging the lever 104. When the lever 10 1 is depressed, as described, the release valve 136 is opened. Chamber 137 is connected by passage 1 11 to the brake cylinder passage 101 so that when the valve 136 is unseated brake cylinder pressure will. flow into the release chamber 99. The release chamber 99 is connected by passage 1 12 to the retention chamber 90. The passage 1&2 is

connected to atmosphere, as will be herein after described under the heading Helease after service-Graduated r lease.

The brake cylinder pressure chamber 100 is connected by passage 143 to port Ltd in the main slide valve seat. In the main slide valve is formed a port 1 15 which is in register with the port 1 14 and is provided at its upper end with a long extension 145. This extension is in register with a port 116 of thesupplemental slide valve and said port is connected by a passage 1&7 to a port 1 18. This latter port is in register with a port 149 of the main slide valve and this port registers with a port and passage 150 which leads to the seat of the releasegoverning valve. The release-governing valve is formed with a cavity 151, which in the quick release position of said valve connects port 150 with port and passage 152, said passage leading to a port 153 in the seat 01" the exhaust valve 31. In said valve is formed a cavity 154 which in the normal position of the valve 31 connects port 153 to an atmospheric port 155.

Passage 142 is connected by a passage 156 to a port 157 in the main slide valve seat. In said passage 156 is a check valve 158 which seats downwardly toward the passage 142. This valve is normally held away from its seat by a light spring but will be Q seated by pressure sufliciently high to overnected passages and ports just described to tniosphere through port 161. The main exhaust, however, will be through the large exhaust 155.

The emergency reservoir E is connected by a passage 162 to a small chamber 163;

la said chamber is arranged a quick revalve which is normally seated spring and closes communication bechamber 163 anda chamber 165. The l valve 164 is adapted to be '1 cy an ad ustable screw in the subinitially horizontal arm 166 of a bell crank lever 167. T he downwardly extending arm this lever is operatively connected to a stem 168 of a quick release plunger 169. This plunger is mounted to reciprocate in a chamber J0 and its outer end subject to press L in chamber and said chamber is connected by a passgae 171 to the brake pipe passage 25 and in this passage is a restriction plug 172 which regulates the flow of air to the brake pipe. In the chamber is arranged a spring which normally holds the plunger 169 in its inner position. Chamber 170 is connected by a passage 173 to a port in the main slide valve seat. The main slide valve is formed with a port 17d which registers with port 173, and the supplemental slide valve is formed with a cavity 175 which connects port 174 to a port 176 of the main 7 slide valve. This latter port registers with a port and passage 177 which leads to a port in the seat of the release governing valve. The release governing valve is formed with a cavity 178 which connects port 177 to a port and passage 1.79 which leads into the quick release chamber 180. \Vith the release-governing valve in quick lit! vided with a leak port 181 so that .the'pressure on opposite sides of said plunger will equalize and permit the spring to force the plunger inwardly, which will result in the closure of the quick-release valve 164. The period of time during which the quickrelease valve will remain open will depend upon the size of the quick-release chamber 180 and thesize of the leak port 181. By properly proportioning these parts .the desired amount of emergency reservoir air may be discharged into the brake pipe. The restriction plug 172'must also be properly proportioned to get the desired result.

If, during the release period, there'should be an excessive pressure in chamber 1, the piston 2 and the supplemental slide valve would be carried to restricted-release and retarded-recharging position as shown ,in F 5. In this position of the supplemen tal slide valve the port 83 is in register with the port 120 so that pressure in chamber 29 will be exhausted to atmosphere tirough port 83, passage 84, and supplemental exhaust port 182 of the supplemental slide valve; This port 182 is in register with a port 183 of the main slide valve and said latter port opens into a large port and cavity 184 in said valve, and said cavity is in register with an atmospheric port 185. The pressure in the releasegoverning valve chamber 29 will force the piston 30 and the valve 81 outwardly to the limit of its movement and this movement of valve 31 will move cavity 154 out of register with port 153 and thereby prevent the exhaust of brake cylinder pressure through the main atmospheric port 155. In this position of the valve 31 brake cylinder pressure will be slowly released past the release valve 136 and thence to atmosphere through the port 161 in the release governing valve. lVhen the pressures on opposite sides of the piston 2 have equalized the spring 5 will move the supplemental slide valve back to normal release and charging position. Air will then flow from chamber 1 into chamber 29 and the valve 31 will be moved to normal open position. In the restricted release position of the supplemental slide valve the re-charging of the emergency reservoir and the auxiliary reservoir will be retarded, as hereinbefore pointed out. In the normal release position of the supple mental slide valve the reservoirs will be recharged as hereinbefore pointed out. The quick release chamber 180 will be vented to atmosphere Whenever the supplemental valve 11 is moved to service position (see Fig. 2). With the supplemental valve in service position airfrom chamber 180 will flow backthrough the connected ports and passages to port 176'in the main slide valve. In the service position of the supplemental slide valve port 176 is connected by a port and passage 186 to the exhaust port 184 of the n a in slide valve. This port 184 is connected to the atmospheric port 185. This arrangement of ports and passages will permit air to flow from chamber 180 to atiiiosph'ere in the service position of the sup-- plemental slide valve.

- When thebrakepipepressure and the auxiliary reservoir pressure have been equalized either by repeated service reductions of brake pipe pressure or by a full service re-' duction thereof, there will be equal pressure inchambers 36 and 38 of the auxiliary reser' voir equalizing valve, 'as' hereinbefore pointed out under the heading Service application. It is also hereinbelore pointed out that when the pressures in chambers 36 and 83 are equal, or substantially so, the auxiliary reservoir iscut oil from the brake pipe and then further. reductions in brake pipe pressure will not reduce the auxiliary reservoir pressure. Under this conditioner" the control valve it is desirable to first release the trapped auxiliary reservoir pressure back into the train pipe, when increasing brake pipe pressure for the purpose of securing a release of the brakes, and this is brought about by the auxiliary reservoir release valve 246, said valve being controlled by the auxiliary emergency valve 73. The auxiliary reservoir passage 61 is connected b a passage 247 to a small chamber 248 and said chamber is connected to a chamber 249. Interposed between said two chambers, and seating toward the chamber 248, is a check valve 250. Chamber 249 is in communication with a small chamber 251 above the release valve 246. A spring 252 holds the valve 246 on its seat. Chamber 251 is in communication with chamber 72 and the check valve 246 normally closes said communication. In the chamber 72 is pivoted a bell crank lever 253, one arm of which is adapted to engage the lower end of the valve 246. The other end of said bell crank lever is operatively connected to the stem 254 of a release plunger 255. This plunger reciprocates in a chamber 256 and the outer face thereoi is exposed to the pressure in chamberv 72 and its inner face is exposed to the pressure in chamber 256. A spring 257 normally holds the plunger in its outer posi tion with its stem against a fixed stop and the lever 253 is in position to permit the valve 246 to seat. Chamber 256 is connected by a passage 258 to a port 259 in the seat of the valve 73. In the valve 78 is formed a cavity 260 which in the release position of the valve 73 connects port 259 to aport and passage 261. The pasage 261 leads into passage 177 and, with said passage, is in communication Withthe quick release chamber 180. This communication is by means of the cavity'178 in the release governing valve, when said valve is in quick release position, and port and passage 179 which leads tochamber 180.' When the valve 73 is in released position chamber 256 is vented to the chamber 180, in the quick release position of the release governing valve, and

. ermittin the ressure .in cham er 1 to move the piston 2 and the mainand supplemental slide valve to release position.

In all quick release operations of the control valve the chamber 256 will be vented to the quick release chamber 180 and the valve 246. will be unseated. However, the pressures in the auxiliary reservoir and in the brake pipe will be substantially equal at all times except when the brake pipe pressure has been reduced below the point of equalization. It is clear, therefore, that the opening of the valve 246 will be a substantially idle operation except when the brake pipe has been reduced below the point of equalization, as hereinbetore pointed out.

Release after semic-Gmduated release.

The control valve is adjusted for graduated-release operations by moving inwardly the release-governing valve 26 to the position shown in Fi 6. In this position of the releasegoverning valve the large exhaust port- 152 in the seat of the release-governing alve is closed. The exhaust port 135 is also closed. Port 161 in the release-governing valve is moved out of register with port 160.

To effect a graduated release of the brakes the brake pipe pressure must be increased in the usual manner a predetermined amount, and the increased brake pipe pressure must be less than the full running pressure or full charging pressure. pipe pressure will How to the chambers 1 and 1 through the equalizing valve chamber, as hereinbefore pointed out in describing the charging operation, and the increasing pressure in chamber 1 will move the piston 2 and the supplemental slide valve to release position, as hereinbeforc described. The increased pressure will flow through the charging port and passage to the auxiliary reser voir, and from said reservoir through passage 62 into the actuating chamber 63. The diaphragms will be moveddownwardly and the valve 93 will be moved to release posi' tion (see Fig. 6). There will be no exhaust from chambers 36, 96 and 89 through port 135 because said port will be closed in the graduated-release position of the releaseg em ng valv n he re e se po tive O The increase in brake valve 93 a passage 18'? is connected b cavity 188' in the valve 93 to a port 189. ort 189 is connected to a passage 190 which leads to a port 191 in the main slide valve seat. Port 191 is connected, through a restricted port, to port 184 of the main slide valve and this latter port is connected to a restricted port which leads to the atmospheric port 185. It is clear, therefore, that in the release position of the valve93 air will flow from the equalizing chamber 89 through the restricted port to the atmospheric port 185. The control chamber 96 and theequalizing chamber 36 are connected to'the equalizing chamber 89 through passage 88, and the ports and passages within communication therewith and with the said chambers, so that the pressures in said chambers 36 and 96 will be 7 reduced with the pressure in chamber 89. The reduction of pressure in chamber 36 will have no effect upon the equalizing valve 11 because of the superior pressure in chamber 33. The reduction of pressure in chamber 96 will permit the superior pressure in the brake cylinder chamber 100 to depress the diaphragms 97 and 98 thereby carrying the release valve lever 10 1 downwardly, and through the pin 140 opening the release valve 1.36. When said valve is open brake cylinder pressure mayflow through passage 1 11, chamber 137, passage 139 into the re lease chamber 99. From the release chamber air willfiow through passage 142 into the retention chamber 90. From said passag 142 air will alsoflow through passage 156 pastcheck valve 158 and thence through passage 192v into passage 190 and thence to of the chamber 180 is added to the volume oi the retention chamber 90 in the graduated release operations.

VVhenthe pressure in chamber 89 has been reduced sufficiently to permit the undis turbed emergency reservoir pressure in chamber 64 to move the diaphragm structure and the valve 93 upwardly to lap position, the flow of air from chamber 89 and chambers 36 and 96 will be stopped. Brake cylinder pressure will continue to flow from chamber until the pressure in chambe 96 is slightly superior to the pressure in chamber 100, whereupon the release valve 136 will be closed; thereby stopping the exhaust of brake cylinder pressure. The pressu e n the actuatin chamber 6 was insure-gradua ing valve 93 to lap positto an equalit crease in brake pipe pressure will be and the release operation will be repeated ]:)l11' during the same interval.

creased a predetermined, amount and the pressure in chamber 89 must be reduced at oressure in ch mber 6% will move the n. I L

in chamber 96 will be reduced with the pressure in shun 89 and that will result in a corresponding reduction or pressure in the brake cylinder and in the brake cvlinder chamber 190.

v 01M13 .ni ,e. i 1% .LL 1 c ocsirct. .o mairea iur aei reoiic tion of bralre cylinder pressure a turther in- The pressure lfit be desired to increase the brake cylinder pressure the brake pipe pressure will be re duced and the application operation will be repeated in the same manner as heroinbefore described.

The flow of brake cylinder pressure to the quick release chamber 160 will cause a quick drop in brake. cylinder pressure and also will prevent .the building up of a hi h pressure in passage 192. Pressure will con tinueto build up in the retention chamber 90 so long as the release valve 136 is open,

and-the pressure in-said chamber will exert an upward force on the diaphragm Z) in opposition to the pressure in chamber 89. amount of pressure which will flow into chamber 90 will depend upon the length 01? time the valve 136 is held open. The air that flows into chamber 90 will blow down to atmosphere around check valve 158, through passages 192 and 199 andthe connected ports and passages to the atmospheric 'port 185. H the release valve 136 is heldopen a suiiicient time to permit brake cylinder pressure to blow down to atmosphere, it is obvious that the pressure in chamber 90 will also blow down to atmos- The pressure is not trapped in chamber 90 but remains therein only temporarily.

The purpose of permittingair to flow into the chamber 90 is to retard the release of control chamber pressure through chamber 89 and the passage 187. When the auxiliary reservoir pressure in chamber 63 has been increased for a release or the brakes,

lease valve 136 will be clos :l.

The

port 19%.

scribed. The pressure built up in chamber 90' will move the. diaphragm structure and the valve 93 upwardly. This upward move ment of the valve 93 will stop the flow of air fr in chamber 89 and chamber hen the brake cylinder pressure has been suliiciently reduced in chamber 109the re- This will stop the How of air to chamber 90, and the air in said chamber 90 will blow down to atmosphere as hereinbei'ore pointed out. ii l en the pressure in chamber 90 has been suihciently reduced the pressuregraduatin valve 93 will be again moved down to release position thereby releasing more pressure in chamber 89 and from the control chamber 96. This pulsating operation of the pressure-graduating valve will continue until thehpressure in the control chamber and chamber 89 has been sufiiciently reducer to permit the emergency reservoir pressure in chamber 64 to counter-balance the force exerted by the pressure in chamber 63 and the pressure retained in chamber 89. T his operation oi the pressure-gmduating valve wili retard the release of brake cylinder pressure.

In passage 190 is arranged a check valve 193 adapted to seat toward the port in the seat of the pressure-graduating valve This valve is held from its seat by a light spring. Air may flow from the valve 93 through passage 190, but the check valve will prevent a back-flow or" air. Any considerable pressure on the valve 193 tending to seat it will overcome the spring and prevent the fiow of air past the check valve. The port 160 in the seat of the releasegoverning valve is connected to an exhaust port 194-, and said exhaust port is norn'ially closed by a plug 195. When it is desired to operate the control valve in graduated release and without the pressure build-up during cycling operations, the plug 195 is removed. This provides a tree :rhaust oi brake cylinder pressure through passage 156 and the connected ports and passages to port 160 in the seat of the release-governing valve and thence to atmosphere through Therefore there will be no buiioup of pressure in the retention chamber 99 and the control valve will operate in graduated release without th pressure build-up during cycling operations.

With the release-governing valve 26 in graduated-release postion port 177 in the eat of the releasegoverning valve will be closed and brake pipe pressure will be maintained on opposite sides of the quick-release plunger 169 so that said plunger will not be moved in release operations.

When the release-governing valve is in graduated-release position the quick-re?ease chamber 180 is connected to the brake cylin der release passage 156 through passage 1T9,

cavity 178 of the release-governingvalve, passage 160, cavity 159 in the main slide valve and port 157 in the main slide valve seat. Passage 156'is connected to the retention chamber 90 by the passage 142. Passage 156 is also connected to the brake cylinder release passage 190 through the restriction plug in passage 192. If the quick rechamber. The check valve 193 will prevent high pressure air passing through passage 190 to the seat of the valve 93.

[finer-967203 application.

An emergency application of the brakes is effected by an emer 'en'cyreduction of brake pipe pressure in the usual manner. An emergency reduction of brake pipe pressure in chamber 24 will result in a corresponding reduction of pressure in supplemental brake pipe chamber 1, because of the open communication between chambers 24 and 1. There Will also be a reduction of pressure in chamber 1 through the passage 22 and the restriction plug 28, but this reduction in chamber 1 will not be as great as the reduction in chamber 1. The piston .2 and the supplemental slide valve will be moved inwardly or toward the right to the limit 0t their travel. The emergency piston 12 will be moved toward the right by the pressure in chamber 1, the servicelap stop spring 16 being compressed. The piston 12 carries a gasket on its outer face which seals on the annular rib 20. This prevents any leakage from chamber 1 around the piston 12. The movement of the piston 12 will. carry the main slide valve to emergency position, as shown in Fig. 4. The pressure in the auxiliary reservoirchamber 6 will hold the supplemental slide valve in its inner position and the pressure in chamber 1 will hold the main slide valve in emergency position. The ports and passages in the supplemental slide valve have no function in the emergency application; therefore, the movement of this valve to its inner position in emergency applications is an idle movement.

The movement of the main slide valve to emergency position places cavity 196 of the main slide valve in position to connect port to port and passage 197 The passage main slide valve seat.

197 is connected to passage 88. Cavity 196 is connected to the main valve chamber 1 2 port 198. It is clear therefore that auxiliary reservoir will equalize into the main valve chamber through port 198 and will I equalize into the chambers 89 and 96. Port 87 in the main slide vaive seat, which is connected to the passa e 88, wil. be closed when the main slide valve is in emergency position so that air cannot, flow from passage S8 to the chamber 36 as hereinbe't'ore described in connection with the service application operation. I

The auxiliary reservoir chamber 6 is connected by passage 61 and a short branch p usage 199 to a chamber 200 below a valve seat 201. Below this valve seat is arran ed valve 202, and below said valve and en g ing its under side is a spring 203. Above 200 isltormed a chamber 204 rne chamber which normally is in open communication w th chamber 200 past the valve 202. In all operations of the control valve, except emergency operations, the valve 202 is held from its seat by auxiliary reservoir pressure in cln cber 200. Connected to chamber 204 is a passage 205 which leads to a port 2 6 in the main slide valve seat. This port is closed by the main slide valve except in the emer gency position of said valve. When the active position by spring 212. Piston is pro *idcd with an outwardly extending stem 21.3 to which is operatively connected the upper end of one arm of a pivoted hcllcrank lever 214. The other arm of said lever engages an emergency bralte pipe vent vaive This valve is located .in chamber 24 and controls a large exhaustport 216. Saidvalve is held seated in all operations of the control valve, except emergency opera tions, by a spring 217. lVhen auxiliary reservoir air is admitted into the chamber 21.0 the piston 211 will be moved outwardly and the ei'nergency brake pipe vent valve will be opened, thereby permitting brake pipe pressure to flow to atmosphere through the large exhaust port 216.

Chamber 218 below the valve 202 is con nected by a passage 219 to port 191. in the In the emergency position oi the main slide valve the large port and cavity 154 connects the port 191 to a the valve 202, and will force said valveup wardly to its seat thereby closing communh. cation betwen passages 199 and 205-. This stops the flow of auxiliary. reservoir air to.

to move the plunger inwardly: This will permit the brake pipe vent valve 215 to close.

The movement of the main slide valve to emergency position will close port and passage 1? 3 and thereby seal chamber 170 and retain pressure therein. This Will prevent any movement of the quick. release piston 169 so that there will be no danger. of the quick release valve opening. The pressure trapped in chamber 170 may leak down and equalize with the pressure in, chamber 165 through the small leak port 181. Upon an emergency reduction of brakepipe pres sure there probably will be a reduction; of. pressure in chamber 165 through thepassage 171 which connects said chamber to the brake pipe passage 25. I

As hereinbetore pointed out emergency reservoir air may flow from the emergency reservoir E through passage 67 into the chamber 66. Chamber 66 is connected by a passage 223 to a chamber 224. An emergency valve 225 normally closes communication between chamber 66 and chamher 224: and this valve is normally held seated by the pressure in chamber 66 and by a spri 226. Tn the chamber 224 is pivoted a bell crank lever 22?, one arm of which is adapted to engage and lift the emergency v2 v-e from its seat. he other arm of said leer is operatively connected to a stem 228 of an emergency plunger 229 which reciprocat n a chamber 2 0. The outer face of positions of the supplemental slide valve the port 233 is connected, by a port 233 in the main slide valve and port- 235 in the supplemental slide valvef .to the main slide ve chamber 1, port 235 having a long foot 236 for thispurpose; It is clear, therethat in all operations of the valvev fo e. cept'emersency operation, the pressures in chambers 22% and 230 will beequalized with the pressure in-the inain valve' chamber 1. In the emergency position of the main slide valve port is connected by acavity 237 in themain'slide valveto an atmospheric.

port 238 so that the chamber 230 will be vented to atmosphere. vull be moved inwardly by pressure in chami .tngcr 229 is subject to'the pressure: n chamber 22 i, while the inner side thereof.

The plunger 229 bar 224 and the emergency valve 225 will be opened to permit emergency reservoir air to flow from chamber 66 into chamber 22% and thence through passage 23 i into the illtll'lSllClQ valve chamber. The main slide valve is formed with an elbow port 1 1 1 which, in the emergency position of said valve, connects the main slide valve chamher with the main brake cylinder port 1&4. The port lei-l opens into the main slide valve chamber through the side of the main slide valve so that. air may flow from the said main valve chamber to the brake cylinder chamber 190 and thence'to the brake pipe.

The emergency reduction of brake pipe. pressure results in a corresponding reduction of pressure in chamber 72 of the 2111iiliz y emergency valve. The pressure in chamber 76 will force the piston toward the right, causing the service stop 75* to compress the service stop spring- The valve 73 will be moved to its extreme emergency position, as shown in Fig. l, and will uncover port 262. This portis connected by passage 263 to chamber 264 below a piston 239 which is mountedto reciprocate in a chamber 240. The piston 239 is formed with an upwardly extending tubular stem which is adapted to receive a depending stein carried by the supplemental emergency vent valve 81. Brake pipe air from cham' her 76 will flow into thechamber 26 i and cause piston 239 to move valve 81 to its open position. Chamber 80 is connected by passage 2&1 to a chamber 242 below the valve 81 and this latter chamber is connected by passage 243 to a large atmospheric port 244. When the valve 81 israised from its seat air may flow from the supplemental brake pipe chamber 1 direct to atmosphere. This ensures a quick movement of the main slide valve to emergency position. lVhen the main slide valve 1s in emer ency position no air can flow through passage 77 to the (hamber 76 because the feed port and passage 53 is closed. In the emergency position of the auxiliary emergency valve 7 3 chamber 79 is sealed and the air trapped therein cannot flow to the brake pipe. The plunger 239 is former with a leak port 239*" to permit the air in chamber 26% to leak down to atmosphere. \Vhen the pressure in chamber 264': has been sufiiciently reduced the spring 82 will seat the valve 81.

VVhen the chamber is vented to mosphere through passage. 25 the spring 123 Wlll move the equalizing valve 41 to lap position. There will be no pressure in cl ber 36 because the port is closed when the main slide valve moves to emergency position. There will be an equalization of the passage 118.

lll)

pressures; chambers 1, and. 26. through. 

